This invention relates to pressure transducers and in particular to a pressure responsive magnetically permeable diaphragm of laminar construction for use in a pressure transducer.
Diaphragms of nonuniform cross-section have been employed in pressure transducers wherein the outer region comprises a rigid integral support and the thickness of the diaphragm near the center is reduced to produce an area of the diaphragm of reduced cross-section where deflection occurs due to subjecting one or both sides of the diaphragm to changing pressure. The rigid integral support of the thicker region of the diaphragm maintains a fixed diameter for the thinner central region to deflect and accurately indicate pressure during temperature gradients and other operating conditions that cause the clamping pressure blocks that hold the diaphragm to deform away from the rigid integral support portion of the diaphragm, thereby maintaining a fixed deflection diameter for pressure indication under a varying clamping diameter.
Diaphragms of nonuniform cross-section have been designed to meet a variety of criteria resulting in varied profiles of the cross-section of a diaphragm designed to meet specific criteria. In order to compete favorably with the flat diaphragm, diaphragms of nonuniform cross-section have typically been machined from a flat diaphragm. The thicker outer portion remains as an integral support while the thinner central region is machined to have a profile to meet the design criteria of the diaphragm application. The machining process may leave machine markings that affect the accuracy of pressure detection and further lead to premature failure of the diaphragm.
What is needed is a diaphragm of nonuniform cross-section that eliminates the machining process thereby eliminating the machine markings that produce inaccurate pressure and lead to premature failure of a diaphragm and further provides for thinner central deflection region than is attainable from a machined diaphragm.